check_weighter_compute_weights_alignment¶

def check_weighter_compute_weights_alignment(weighter, key: pl.Series) -> None:
    """Check ``compute_weights`` returns one weight per key element.

    Parameters
    ----------
    weighter : BaseWeighter
        Weighter instance.
    key : pl.Series
        Key series to weight.

    Raises
    ------
    AssertionError
        If the output is not a ``pl.Series`` aligned 1:1 with ``key``.

    """
    name = type(weighter).__name__
    weights = weighter.compute_weights(key)
    assert isinstance(weights, pl.Series), f"{name}.compute_weights must return pl.Series, got {type(weights)}"
    assert len(weights) == len(key), (
        f"{name}.compute_weights returned {len(weights)} weights, expected {len(key)} (one per key element)"
    )